An albumin, particularly human serum albumin (hereinafter also referred to as HSA) is an important component constituting protein in plasma. This protein is produced in liver, and is mainly responsible for sustaining normal osmotic pressure of blood flow. Also, it functions as a carrier for various serum molecules.
HSA is administered in a variety of clinical situations. For example, when HSA is administered to a patient suffering from shock or ambustion, it functions to recover blood volume to its original level, thereby improving some symptoms relating to trauma. For this effect, HSA is frequently administered. Also, patients suffering from hypoproteinemia or fetal erythroblastosis may need treatments with HSA. As exemplified, the basic significance of HSA administration is prominent in the treatment of symptoms accompanying loss of fluids from blood vessels, as in surgery, shock, burn, or hypoproteinemia which causes edema.
At present, HSA is produced mainly by fractionation of blood. This production method is uneconomical, and besides, it poses a problem that the supply of the blood from which HSA is produced is not always assured. Moreover, since HSA is blood-originated, HSA produced in this way is under a constant risk of containing undesirable substances such as hepatitis viruses. From this aspect also, development of a substitute for blood as the raw material for HSA will be greatly advantageous.
Under the circumstances as described, methods for a large-scale production of HSA by genetic engineering, followed by high purification is being established. Such method will permit economical production of HSA containing no undesirable substances such as hepatitis viruses.
By genetic engineering, however, HSA is colored by being combined with a certain coloring component present in raw materials or by the contamination of substances secreted by microorganisms during culture of host microorganisms and/or during purification of HSA. These contaminants cannot be removed sufficiently by conventional purification methods for plasma-originated HSA.